Re: maintainer-makefile: catch uses of $< in non-implicit rules

[Akim Demaille]

Hi Tim,

> Le 17 juin 2019 à 12:04, Tim Rühsen <address@hidden> a écrit :
> 
> Hi Akim,
> 
> On 6/17/19 11:59 AM, Akim Demaille wrote:
>> Hi Tim,
>> 
>>> Le 17 juin 2019 à 11:57, Tim Rühsen <address@hidden> a écrit :
>>> 
>>> Hi Akim,
>>> 
>>> The patch uses awk -e which is understood only by GNU awk. This breaks
>>> all Debian CI tests here since Debian installs 'mawk' by default (I
>>> wasn't aware of that before).
>>> 
>>> It's not a big deal to install package 'gawk' everywhere, but I just
>>> wanted to mention it. I can see no warning/hint in any of the patch's
>>> comments.
>> 
>> That was not my intention.
>> 
>> I expect that maintainers have gawk installed, so I think this check
>> should be skipped if awk is not gawk.  WDYT?
> 
> Thanks, sounds reasonable to me.

Here is my proposal.  Worked properly with the non GNU awk sitting on my 
machine.

commit b70c97f3ecf45a5c98b7f32189c1a4ae72a60788
Author: Akim Demaille <address@hidden>
Date:   Sat Jun 22 17:52:16 2019 +0200

    maintainer-makefile: restore portability to non-GNU awks
    
    Reported by Tim Rühsen.
    * top/maint.mk (AWK): New variable.  Use it.
    (sc_prohibit_gnu_make_extensions): Skip if $(AWK) is not gawk.

diff --git a/ChangeLog b/ChangeLog
index cdc2b3d7a..dc7e52c0a 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,10 @@
+2019-06-22  Akim Demaille  <address@hidden>
+
+       maintainer-makefile: restore portability to non-GNU awks
+       Reported by Tim Rühsen.
+       * top/maint.mk (AWK): New variable.  Use it.
+       (sc_prohibit_gnu_make_extensions): Skip if $(AWK) is not gawk.
+
 2019-06-22  Akim Demaille  <address@hidden>
 
        argmatch: put all the docs member last.
diff --git a/top/maint.mk b/top/maint.mk
index 3dbe9c378..16e936022 100644
--- a/top/maint.mk
+++ b/top/maint.mk
@@ -24,6 +24,7 @@ ME := maint.mk
 # These variables ought to be defined through the configure.ac section
 # of the module description. But some packages import this file directly,
 # ignoring the module description.
+AWK ?= awk
 GREP ?= grep
 SED ?= sed
 
@@ -190,7 +191,7 @@ $(sc_z_rules_): %.z: %
        @end=$$(date +%s.%N);                                           \
        start=$$(cat .sc-start-$*);                                     \
        rm -f .sc-start-$*;                                             \
-       awk -v s=$$start -v e=$$end                                     \
+       $(AWK) -v s=$$start -v e=$$end                                  \
          'END {printf "%.2f $(patsubst sc_%,%,$*)\n", e - s}' < /dev/null
 
 # The patsubst here is to replace each sc_% rule with its sc_%.z wrapper
@@ -435,13 +436,15 @@ sc_prohibit_gnu_make_extensions_awk_ =                    
                \
      exit status;                                                      \
   }
 sc_prohibit_gnu_make_extensions:
-       (cd $(srcdir) && autoconf --trace AC_CONFIG_FILES:'$$1') |      \
-         tr ' ' '\n' |                                                 \
-         $(SED) -ne '/Makefile/{s/\.in$$//;p;}' |                      \
-         while read m; do                                              \
-           $(MAKE) -qp -f $$m .DUMMY-TARGET 2>/dev/null |              \
-             awk -v file=$$m -e '$($@_awk_)' || exit 1;                \
-         done
+       @if $(AWK) --version | grep GNU >/dev/null 2>&1; then           \
+         (cd $(srcdir) && autoconf --trace AC_CONFIG_FILES:'$$1') |    \
+           tr ' ' '\n' |                                               \
+           $(SED) -ne '/Makefile/{s/\.in$$//;p;}' |                    \
+           while read m; do                                            \
+             $(MAKE) -qp -f $$m .DUMMY-TARGET 2>/dev/null |            \
+               $(AWK) -v file=$$m -e '$($@_awk_)' || exit 1;           \
+           done;                                                       \
+       fi
 
 # Using EXIT_SUCCESS as the first argument to error is misleading,
 # since when that parameter is 0, error does not exit.  Use '0' instead.
@@ -1383,7 +1386,7 @@ gpg_key_ID ?=                                             
                \
   $$(cd $(srcdir)                                                      \
      && git cat-file tag v$(VERSION)                                   \
         | $(gpgv) --status-fd 1 --keyring /dev/null - - 2>/dev/null    \
-        | awk '/^\[GNUPG:\] ERRSIG / {print $$3; exit}')
+        | $(AWK) '/^\[GNUPG:\] ERRSIG / {print $$3; exit}')
 
 translation_project_ ?= address@hidden